On Wed, Aug 13, 2014 at 8:55 PM, Emmanuel Dreyfus <[email protected]> wrote:
> Anand Avati <[email protected]> wrote: > > > That may / may not work well in practice depending on the number of > > concurrent apps working on a file. > > I am not sure what could make a FS decide that for the same file, one > file descriptor should use direct I/O and another should not. > > Keeping the flag at file descriptor level would require VFS modification > in the kernel: the filesystem knows nothing about file descriptors, it > just know vnodes. It could be done, but I expect to meet resistance :-) > > For e.g, glusterfs used to enable directio mode for non-read-only FDs (to cut overheads) but disable directio for read-only (to leverage readahead). After big_writes was introduced in Linux FUSE this has changed. But we should be OK having vnode level switch for now, I think.
_______________________________________________ Gluster-devel mailing list [email protected] http://supercolony.gluster.org/mailman/listinfo/gluster-devel
